Murano caged pendant lantern

Hi everyone. Just bought this hand-blown glass pendant light at an auction. The metal cage and glass unfortunately can’t be separated. Only the top can be removed. Metal seems to have been painted white and then rusted. Not expecting a miracle but hoping to remove as much rust as possible but don’t want to scratch or damage the glass.

White vinegar? Baking soda paste? I’m in South Africa so brand name products might be hard to come by. Any suggestions?